What kind of food that can help me gain weight?

At the end of the: Day you will need lots of high quality calories, especially plenty of protein and avoid refined sugar.

Eat healthy foods: Foods to help w weight gain: almonds, cashews, pecans, sunflower seeds, flax seeds, walnuts, hummus, avocados, granola, trail mix, dried fruits, protein shakes & bars, lean meats, poultry, fish, smoothies (with added silken tofu or powdered milk), extra virgin olive oil, canola oil Greek yogurt (full –fat), pasta/ bagels & use of juice rather than soda. Some people add whey proteins.